Show clearly that (3√3)^2 = 27
Show clearly that (3√3)2 = 27
First of all, the question looks overfacing due to the surds, I can assure you that surds are not scary, they simply act as a means of clearing up messy numbers such as 1.73205 08075 68877 29352 74463... (carries on for a billion digits) which can be simply written as √3!
So, how would we work out (3√3)2 without using a calculator? Well, luckily the question tells us that the answer we need to find is 27, so we can't go far wrong within these parametres.
First of all, (3√3)2 is a tidy and mathematical way of writing 3√3 x 3√3.
A surd is not an equation, it is just a tidy way of writing a messy number.
Remember the rule of surds:
√(a x b) is the same as √a x √b...
3√3 is a tidy, surdy way of writing √32 x √3. Which is the same as √9 x √3... √(9 x 3).... which can also be written as √27.
so, what we have to show is that √272= 27.
√27 x √27= 27, because, by timesing together two like surds, we can get rid of the root sign because, in general, multiplying two like surds gives a rational number... (√a x √a= a) (2√a x √a=2a)
Hence, we have just proved that (3√3)2= 27 simply by referring to the basic rules of surds :)
